There was a big push by TV cooks a few years back to emphasise that things can be eaten past sell-by dates rather than just throw them away. I embraced this principle a good few times, but I know since that I can projectile vomit into my bath but only being able to half-aim a torent of diarrhea very roughly in the direction of my toiet bowl at the same time, just before my forehead hits the bathroom floor in front of me in a bizare and excrutiating pool of puke, feces and uncontrollable spasms and sweat pouring out of me while my body starts to shake. The puke sems to make it to the bath, the diahrea always seemed to make it in strange places and up the wall. Some bits I only found weeks later. I therefore gave up a few years ago with this talk of eating stuff past the marked sell by dates, despite applying prefectly good rational. I usually always discard food if it's past the date now. Personally I conentrate these days on only buying enough food to last until I can eat it. BUT I am not the only person I know who finds it increasingly more difficult to shop for one these days. You are always pushed towards bigger packets of food, deals you can't get through before they go rotten. All the good deals on fresh food seem increasingly impossible to buy without throwing lots away if you are only able to eat a portion for one each night.
...I'm very impressed by the milk industry though. I have experienced it countless times so far -a bottle of milk is OK the day before expiry, the next day -even an hour past midnight it's curdled like yoghurt, sour, totally inedible -no debate. I have never seen any other product go that way so exactly and consistently. I've had bottles of milk "fizz" / ferment just one hour into the next day past expiry when they were perfectly OK 2 just hours before. I hate pouring milk away but it seems to have a very exact shelf life with no debate at all!
...sugar and salt are my ecxeptions and the internet says sugary and salty things are apparently exempt from the 10s rule if you drop them. I have a 1kg bag of sugar which has a use by date of 2004 -I still use it which probably says allot about my sugar intake as its still half full (I've never had any upset stomachs using this yet).